1. Field of the Invention
The present invention relates to surgical appliances, and particularly to a frame placed on a conventional surgical operating table which positions the patient in a prone position for spinal surgery, and is especially suited for positioning the patient for a lumbar laminectomy with spinal fusion.
2. Description of the Related Art
Surgery on the spine is usually performed in either the lateral recumbent or the prone position. The lateral recumbent position is usually used for procedures where both an anterior and posterior approach are used. However, the position does not permit a wide view of the intervertebral disks and it is difficult to control bleeding. Therefore, a prone position is normally used for a posterior approach.
Originally the prone position simply involved having the patient in a recumbent position with his abdomen on the surface of the operating treatment. However, in this position there was copious bleeding due to pressure on the inferior vena cava. It was found that there was less bleeding if the patient were elevated so that the abdomen was distended and might hang freely. The simplest method for accomplishing this is to position chest rolls or bolsters on the table under the axillae and along the sides of the chest from clavicles to iliac crests. However, this has not been found to be completely satisfactory, and a number of devices for positioning the patient in a prone position with the abdomen distended have been developed. A number of devices may be distinguished by the degree to which the hips and knees are flexed.
German Patent No. 882,476, published Oct. 23, 1952, shows an adaptor for a surgical table having a T-connector for supporting the hips which attaches to leg support brackets of a conventional surgical table. A system of bars describing a U-shape is attached to the bottom of the T-connector. The other upright of the U-shape has supports under the axillae, a support for the upper chest, a head support and arm supports. While the abdomen is distended, the T-connector may produce enough pressure across the pelvis to impair venous return, and the use of shoulder supports directly under the axillae is questionable due to the possibility of impaired blood flow and damage to the brachial plexus. The device is not currently used.
The Relton-Hall frame is described in J. Bone Joint Surg. [Br], 49(2), 327 (1967). An example of positioning the patient on a Relton-Hall frame is shown in "Positioning Techniques in Spinal Surgery", R. A. Callahan and M. D. Brown, Clinical Orthopaedics and Related Research, Jan.-Feb. 1981, No. 154, pp. 22-26. The Relton-Hall frame is a frame which is placed on top of a conventional operating table, the frame having a generally rectangular base frame, four vertical posts clamped onto the frame and adjustable longitudinally and laterally, and pads having a 45.degree. inward tilt at the top of the vertical posts. The pads are positioned under the antero-lateral aspects of the pelvic girdle and under the lateral aspects of the upper thoracic cage as close to the midline as possible. The hips may be flexed up to 60.degree.. One problem with the Relton-Hall frame is that intraoperative x-rays are rendered difficult by the metal frame.
A modification to the Relton-Hall frame to overcome this problem is shown in "A Radiolucent Spine Frame: A Modification of the Relton-Hall Spine Frame", Kumar, et al., Journal of Pediatric Orthopaedics, 14:383 (1994). The modification describes a base composed of two sheet layers having a space between the two layers for containing an x-ray cassette. The base measures 35".times.18", the bottom layer comprising high density polyethylene glued to soft Aliplast, the top layer comprising Plexiglass covered by Velcro.RTM.. Four vertical support posts are attached to the base by Velcro.RTM. strips, the top of the posts being tilted at a 45.degree. angle and capped with pads of vinyl-covered temper foam.
A Hastings frame is described in "A Simple Frame for Operations on the Lumbar Spine", D. E. Hastings, The Canadian Journal of Surgery, 12:251 (1969). The frame includes a pair of parallel horizontal beams, a pair of parallel vertical posts mounted at right angles to the beams, a pair of diagonal struts between the beams and posts, a seat mounted between the vertical posts, an adjustable cross beam placed between the struts about the patients feet, and a pair of metal straps on the vertical posts for mounting the frame to the operating table. The patient is placed on the table in the knee-chest position with the buttocks against the seat, the feet against the cross beam, the chest supported on a box between four and eighteen inches high, depending on whether a spinal fusion is being performed, and the table is tilted in a reverse Trendlenberg to position the spine horizontally in a prone position. The hips are hyperflexed somewhat more than 90.degree., flexing the lumbar spine to spread the vertebrae and provide open access to the disks, while also reducing hemorrhage.
An improved kneeling attachment for an Andrews frame is described in U.S. Pat. No. 4,662,619, issued May 5, 1987 to Ray, et al. The Andrews frame includes a rigid thigh support pivotally attached to an operating table, the thigh supports having a rail on either side, rigid lower leg supports slidingly and lockably engaging the rails, and a rack and pinion drive for sliding the lower leg platform up and down on the rails, the Ray patent describing improvements in the kneeling attachment. The Andrews frame has since been improved to a table, as described in U.S. Pat. No. 5,444,882, issued Aug. 29, 1995 to Andrews, et al. The table includes a plurality of hydraulic cylinders for adjusting segments of the operating table and rotating the table. The patient lies flat on the table with the hips extended, the lower leg support is rotated to flex the knees at 90.degree. vertically, the thigh supports are rotated to 60.degree. to place the patient in a prone kneeling position, in which x-rays may be taken through a "radiolucent opening", and the thigh supports are rotated to the operative position, in which both the hips and knees are flexed at 90.degree..
The Wilson frame is shown as prior art in FIGS. 1 to 4 in U.S. Pat. No. 5,584,302, issued Dec. 17, 1996 to Sillaway, et al., and photographically in Alexander's Care of the Patient in Surgery, published by Mosby in 1995 at p. 107. The Wilson frame includes a pair of spaced apart panels on a base frame, the panels being flexible and the base being adjustable by a hand crank mechanism which arches the panels. The patient is supported by pads on the panels extending from about the axillae to the hips. With the patient lying prone on the flat frame, the surgeon may raise the panels using the crank to obtain the desired flexion of the spine.
The Jackson table is shown in U.S. Pat. Nos. 5,088,706, issued Feb. 18, 1992, and 5,131,106, issued Jul. 21, 1992, to R. P. Jackson. The Jackson table includes a U-shaped base in a horizontal plane with vertical end supports and a pair of hydraulic lifts. A pair of vertical posts rising from the end members is equipped with a rotating mechanism. An open, rectangular patient support frame having a fabric stretched across its lower end for support of the patients legs is removably mounted in the rotating mechanism. The table has two pairs of pads mounted on the sides of the rectangular patient support frame for support of the antero-lateral aspects of the pelvis and a pair of pads for support of the lateral aspects of the thoracic area. The frame is adjustable longitudinally, but only in conjunction with changing the angle of the bed, and the patient support frame is apparently not adjustable laterally, since the ends of the rectangular frame comprise rigid, U-shaped structures. The '106 patent added a strap about the hips to hold the patient prone and altered the pads, providing a pair of pads to support the chest, hips, and thighs, respectively, the chest pads being larger than the hip and thigh pads and being angled towards the patient's head, all of the pads being trapezoidal in shape and angled downwards towards the centerline. The Jackson table may support the patient with the hips flexed about 30.degree..
U.S. Pat. No. 5,009,407, issued Apr. 23, 1991 to R. S. Watanabe, shows a surgical table for microscopic lumbar laminectomy surgery having a horizontal base, vertical columns at each end of the base, one of the columns supporting a knee rest and the other supporting a cantilevered table top with shoulder rests and hip rests, the height of the columns being adjustable and the table top also being adjustable angularly around a pivot transverse through the vertical column. The table positions the patient with the hips and knees flexed 90.degree..
Other devices considered less relevant include: U.S. Pat. No. 516,587, issued Mar. 13, 1894 to A. H. Campbell (combination sofa, chair, and surgeon's table); U.S. Pat. No. 4,579,111, issued Apr. 1, 1986 to J. C. Ledesma (pad to prevent lumbar laminectomy patient from rolling during surgery); and U.S. Pat. No. 5,014,375, issued May 14, 1991 to Coonrad, et al. (resilient foam surgical pad with hole in the center to support the torso).
Each of the above frames and tables have their advantages and disadvantages, the choice of the device often being dictated by the particular surgical procedure. Frames which support the patient with the hips and knees flexed at least 90.degree., such as the Andrews table and Hastings frame, offer wide exposure of the lumbar disks and reduced bleeding. However, recent studies have indicated that when spinal fusion with instrumentation or surgical procedures involving internal fixation are concerned, it is important to maintain an intraoperative curvature of the spine close to the normal lordotic curve of the spine in the standing position, for which the Jackson table, four poster frames like the Relton-Hall, and other frames which support the patient with 60.degree. or less flexion of the hips are better suited, although some studies show that the four poster frames are less effective in doing so than chest rolls. See Guanciale, et al., Spine, 21(8), 964 (1996), Peterson, et al., Spine, 20(12), 1419 (1995), Stephens, et al., Spine, 21(15), 1802 (1996), Tan, et al., Spine, 19(3), 314 (1994). In addition, for such procedures it is important to have the capacity for performing C-arm fluoroscopy or x-rays intraoperatively to ensure proper alignment. A third consideration is cost, surgical tables with hydraulic equipment designed particularly for prone position surgery being more expensive and less compact and portable than frames used in conjunction with standard operating tables.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a prone surgical positioning frame solving the aforementioned problems is desired.